The present invention relates to an apparatus for and method of lubricating a bearing supporting a rotating shaft in general and in particular to an apparatus for and method of lubricating the upper bearing members of a distributor for an internal combustion engine.
A distributor for an internal combustion engine typically comprises a cup-shaped housing for housing movable electrical-mechanical parts. Extending from the bottom of the cup-shaped housing there is provided an elongated tubular housing for housing a rotatable shaft for operating the movable electrical-mechanical parts. At the lower part of the tubular housing there is provided a bearing sleeve. At the upper part of the tubular housing, immediately adjacent to the cup-shaped housing, there is provided a shoulder for receiving a ring of ball bearings or an annular bearing sleeve.
The distributor housing and upper and lower bearing members described are provided for rotatably supporting the above described shaft on which is mounted a distributor plate. The distributor plate is provided for supporting the above described electrical-mechanical components of the distributor which are used in the operation of the engine in which the distributor is inserted. Forming no part of the present invention, these components are neither shown or further described herein.
When assembled in the shaft housing, the lower portion of the distributor shaft extends beyond the housing and is fitted with a gear member or the like. The gear member is provided for engaging a corresponding gear in the compartment into which the distributor is inserted such as the crankcase compartment of the engine.
During normal operation of the engine, the crankcase is filled with a predetermined quantity of engine oil for purposes of lubricating the moving parts in the engine. The lower part of the distributor including the distributor gear, lower shaft bearing and housing are immersed in the oil and adequately lubricated by the engine oil in the crankcase. In practice, however, the upper bearing comprising the upper shoulder and upper ball bearing ring or annular ring member, are not lubricated by oil from the crankcase because of their relative distance from the lower open end of the distributor shaft housing. This is because oil does not ordinarily migrate upward along the shaft to the extent necessary to lubricate these bearing parts.
Unless bearing parts are made of specific materials and are used in such a manner that they do not require lubrication, lubrication is typically required to prevent premature bearing failure and malfunction of the apparatus in which the bearing is used.
Heretofore, various proposals and attempts have been made to prevent premature failure of the upper bearing parts in conventional distributors. For example, in some of the proposals the bearing parts have been made out of materials and have been fabricated in such a way that no lubrication is necessary following manufacture. These types of bearings are typically known as permanently lublubricated bearings.
In practice, the use of permanently lubricated bearings in a distributor has not been altogether successful because of the operating conditions in which the distributor is used including gross changes in temperature and humidity and also because such bearings are relatively expensive to manufacture.
In still other proposals, grease fittings have been provided for greasing the upper bearing. In practice, however, regular maintenance procedures often result in excessive lubrication in which grease is forced up into the movable electrical parts of the distributor in the cup-shaped portion of the distributor housing causing premature failure of these parts. Because of this problem most manufacturers of distributors no longer employ such fittings.
In still another proposal for lubricating the upper bearing of a distributor, spiral grooves have been provided in the rotating shaft for propelling lubricating oil upwardly into the upper bearing in the manner of an archimedes screw. The provision of such lubricating grooves in the shaft, while suitable for the purpose, is time consuming and expensive.
For the reasons described above with respect to the disadvantages associated with the various prior known methods and apparatus for lubricating the upper bearing members in an internal combustion engine distributor, few efforts have heretofore been successful. As a consequence, upper bearing failure is considered to be one of the most prevalent reasons for distributor malfunction.